discourse/app/models/concerns/positionable.rb
Sam 5f64fd0a21 DEV: remove exec_sql and replace with mini_sql
Introduce new patterns for direct sql that are safe and fast.

MiniSql is not prone to memory bloat that can happen with direct PG usage.
It also has an extremely fast materializer and very a convenient API

- DB.exec(sql, *params) => runs sql returns row count
- DB.query(sql, *params) => runs sql returns usable objects (not a hash)
- DB.query_hash(sql, *params) => runs sql returns an array of hashes
- DB.query_single(sql, *params) => runs sql and returns a flat one dimensional array
- DB.build(sql) => returns a sql builder

See more at: https://github.com/discourse/mini_sql
2018-06-19 16:13:36 +10:00

37 lines
979 B
Ruby

module Positionable
extend ActiveSupport::Concern
included do
before_save do
self.position ||= self.class.count
end
end
def move_to(position_arg)
position = [[position_arg, 0].max, self.class.count - 1].min
if self.position.nil? || position > (self.position)
DB.exec "
UPDATE #{self.class.table_name}
SET position = position - 1
WHERE position > :current_position and position <= :new_position",
current_position: self.position, new_position: position
elsif position < self.position
DB.exec "
UPDATE #{self.class.table_name}
SET position = position + 1
WHERE position >= :new_position and position < :current_position",
current_position: self.position, new_position: position
else
# Not moving to a new position
return
end
DB.exec "
UPDATE #{self.class.table_name}
SET position = :position
WHERE id = :id", id: id, position: position
end
end